The invention makes reference to a state of the art as disclosed, for example, in German Patent Disclosure DE-A1-3541584. A method disclosed in this patent publication is used for producing metal composites consisting of a basic material with at least one metal and further active components. In this case, a substrate made of a basic material is melted down to a preset depth in a locally selected area by means of radiant energy and the active component is supplied to the metal material. This requires radiation with very high beam current density, such as a laser beam, for example, and special energy transmission devices, by means of which the active component can be accelerated to high speeds.
It is known from Swiss Patent Disclosure CH-A5-661616 to expose a sinter body containing chrome and copper in a vacuum or an inert gas atmosphere to a highly concentrated heat flow, for example supplied by an electrical arc, having a beam current density of 10 to 1000 kW/cm.sup.2. In the course of the application of the heating current, lasting approximately 21 to 100 ms, the surface of the work piece is melted open. By means of subsequent cooling of the sinter body at a speed of 10.sup.4 to 10.sup.5 K/s, a contact piece for a vacuum switch is then formed, having a surface layer up to 3 mm thick and made of a finely dispersed copper-chrome material having a low gas content. Contact pieces produced in this manner considerably increase the operational reliability of vacuum switches, but require considerable apparatus outlay when producing contact pieces of large area.